The 17-year-old charged in recent robberies and the arsons of two court buildings had a prior criminal record.

Martavious Semaj Carter, 17, is facing 31 charges related to five armed robberies around downtown Lancaster since Aug. 21. He is also charged with setting the fires at the Lancaster County Courthouse and the 6th Circuit Solicitor's Office last month.

According to State Law Enforcement Division records, Carter was charged with second-degree burglary in June 2007. He went to court in August 2007 and was sentenced under the Youthful Offender Act to six years, suspended to four years of probation.

Carter was arrested on several counts of first- and second-degree burglary from incidents on March 13, 16 and 22, and was awaiting trial on those charges when the courthouse burned Aug. 4.

Carter was not enrolled in the Lancaster County School District, school officials said.

However, Lancaster Police Chief Hugh White confirmed Tuesday that Carter confessed to the two arsons.

"And, yes, the police department has evidence against him," White said. "He knew things about those arsons very few people would know about."

The arson cases remain under investigation, and more charges are possible, White said.

White commended his officers for their work on the robberies, which occurred at Gregory and Gregory law firm, the Lancaster post office, Founders Federal Credit Union and Elizabeth Ann Interiors and Gifts, where the last robbery occurred Thursday. Each person was alone in the parking lot or inside each location when he or she was robbed.

In four of five of the incidents, the victim's car was stolen and abandoned only a few blocks away.

"The officers worked hard, they worked long hours and put a lot of time into these investigations," White said. "They're to be commended. I don't take any credit for this."

In the last robbery on Thursday, a 70-year-old woman was pushed into the trunk of her car after she tried to run from Carter, according to police reports. Her car was abandoned in a field behind Eastside Academy and the woman pried herself out of trunk with a small garden spade.

The fires brought agents from SLED and the federal Bureau of Alcohol, Tobacco, Firearms and Explosives to Lancaster for the investigations. That meant extra officers were on hand to respond when the robberies started happening.

"I couldn't ask for better teamwork," White said. "It was a collaborative effort. We also had a lot of support from citizens and from outside agencies."